fix: add popup to shopping cart

packages/flutter_shopping_cart/lib/src/config/shopping_cart_config.dart

@@ -1,5 +1,6 @@
 import "package:flutter/material.dart";
 import "package:flutter_shopping/flutter_shopping.dart";
+import "package:flutter_shopping_cart/src/widgets/product_item_popup.dart";
 
 Widget _defaultNoContentBuilder(BuildContext context) =>
     const SizedBox.shrink();
@@ -53,6 +54,7 @@ you must use the onConfirmOrder callback.""",
     Locale locale,
     Product product,
     ProductService<Product> productService,
+    ShoppingCartConfig configuration,
   ) productItemBuilder;
 
   final Widget Function(BuildContext context) _noContentBuilder;
@@ -115,6 +117,7 @@ Widget _defaultProductItemBuilder(
   Locale locale,
   Product product,
   ProductService<Product> service,
+  ShoppingCartConfig configuration,
 ) {
   var theme = Theme.of(context);
   return Padding(
@@ -128,10 +131,19 @@ Widget _defaultProductItemBuilder(
             product.name,
             style: theme.textTheme.titleMedium,
           ),
-          Icon(
+          IconButton(
+            onPressed: () async {
+              await showModalBottomSheet(
+                context: context,
+                backgroundColor: theme.colorScheme.surface,
+                builder: (context) => ProductItemPopup(product: product, configuration: configuration)
+              );
+            },
+            icon: Icon(
               Icons.info_outline,
               color: theme.colorScheme.primary,
             ),
+          ),
         ],
       ),
       leading: ClipRRect(

packages/flutter_shopping_cart/lib/src/config/shopping_cart_localizations.dart

@@ -8,6 +8,7 @@ class ShoppingCartLocalizations {
     this.placeOrder = "Order",
     this.sum = "Subtotal:",
     this.cartTitle = "Products",
+    this.close = "close",
   });
 
   /// Locale for the shopping cart.
@@ -26,4 +27,7 @@ class ShoppingCartLocalizations {
   /// Title for the shopping cart. This title will be displayed at the top of
   /// the shopping cart.
   final String cartTitle;
+
+  /// Localization for the close button for the popup.
+  final String close;
 }

packages/flutter_shopping_cart/lib/src/widgets/product_item_popup.dart

@@ -0,0 +1,65 @@
+import "package:flutter/material.dart";
+import "package:flutter_shopping/flutter_shopping.dart";
+
+/// A popup that displays the product item.
+class ProductItemPopup extends StatelessWidget {
+  /// Constructor for the product item popup.
+  const ProductItemPopup({
+    required this.product,
+    required this.configuration,
+    super.key,
+  });
+
+  /// The product to display.
+  final Product product;
+
+  /// Configuration for the product page.
+  final ShoppingCartConfig configuration;
+
+  @override
+  Widget build(BuildContext context) {
+    var theme = Theme.of(context);
+
+    return SingleChildScrollView(
+      child: Padding(
+        padding: const EdgeInsets.all(32),
+        child: SizedBox(
+          width: double.infinity,
+          child: Column(
+            children: [
+              Text(
+                product.description,
+                style: theme.textTheme.bodySmall,
+                textAlign: TextAlign.center,
+              ),
+              Padding(
+                padding: const EdgeInsets.only(top: 20, left: 40, right: 40),
+                child: SizedBox(
+                  width: double.infinity,
+                  child: FilledButton(
+                    onPressed: () => Navigator.of(context).pop(),
+                    style: theme.filledButtonTheme.style?.copyWith(
+                      backgroundColor: WidgetStateProperty.all(
+                        theme.colorScheme.primary,
+                      ),
+                    ),
+                    child: Padding(
+                      padding: const EdgeInsets.symmetric(
+                        horizontal: 16.0,
+                        vertical: 8.0,
+                      ),
+                      child: Text(
+                        configuration.localizations.close,
+                        style: theme.textTheme.displayLarge,
+                      ),
+                    ),
+                  ),
+                ),
+              ),
+            ],
+          ),
+        ),
+      ),
+    );
+  }
+}

packages/flutter_shopping_cart/lib/src/widgets/shopping_cart_screen.dart

@@ -54,6 +54,7 @@ class ShoppingCartScreen<T extends Product> extends StatelessWidget {
                       configuration.localizations.locale,
                       product,
                       configuration.productService,
+                      configuration,
                     ),
                   // Additional whitespace at the bottom to make sure the
                   // last product(s) are not hidden by the bottom sheet.
@@ -216,7 +217,7 @@ class _DefaultSumBottomSheet extends StatelessWidget {
           ),
           const Spacer(),
           Text(
-            totalPrice.toStringAsFixed(2),
+            "€ ${totalPrice.toStringAsFixed(2)}",
             style: theme.textTheme.bodyMedium,
           ),
         ],